Internal combustion engine



Oct. 13, 1936. H. M. ROCKWELL 2,057,164

INTERNAL COMBUSTION ENGINE Original Filed April 21, 1928 COMP.

EXP

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Fatented Oct. 13, 1936 UNITED STATES INTERNAL COMBUSTION ENGINE Hugh M. Rockwell, Freeport, N. Y.

Substitute for application Serial No. 271,725, April 21, 1928. This application December 20,

1932, Serial No. 848,115

3 Claims. (CL 123-30) This invention relates to improvements in in-v ternal combustion engines, and has particular reference to such engines which are adapted for use in aeroplanes, automobiles, and the like.

5 Internal combustion engines using light hydrocarbon fuels have usually been equipped with carbureters from which the fuel is drawn into the engine cylinders by suction. While a number of commercially available carbureters have been successful from the standpoint of engine efficiency, they have not beenentirely reliable and have given rise to objections in aviation work because of their weight. It is therefore one object of this invention to provide novel and simple means for injecting'the fuel to the engine cylinders at properly timed intervals in their working cycles.

Another object of the invention is to provide such injecting means which will measure out a definite amount of fuel for each charge, and which makes use of pneumatic pressure to inject fuel into the cylinders.

Another object is to provide an engine withnovel crankshaft bearings which will permit 05 slight relative movement between thecrank shaft 40 Each of the cylinders has a single valve to con trol admission of air and exhaust of the products of combustion, and associated with the crank shaft is a rotatable fuel measuring member whichperiodically opens and closes a fluid conduit ex- 45 tending from the head end of one cylinder to the head of the other cylinder. While said fluid conduit is closed, it receives in a recess, a definite amount of gasoline or other hydro-carbon fuel, and as this recess comes into communication with the fluid conduit the gasoline is blown into one of the cylinders by pressure from the othercylinder. In the next revolution, the gasoline is blown into the other cylinder, and so it alternates between the two cylinders. The parts are 55 so arranged and synchronized that as one cylinand crank case due to difference in expansion and der is drawing in air the other is exploding, and it is the pressure of the successive explosions which eflects the fuel injection. In this respect the invention is not restricted since the injection of the fuel may take place at any part of the r 5 compression stroke, and can be effected by the transfer of any higher pressure from one cylinder to another. Furthermore. the injection of the fuel by a pump or other mechanical means, instead of by transferred pressure, is also within 10 the contemplation of the invention.

Another feature of the invention is the novel crank shaft and mounting therefor which contributes to the compactness and lightness in weight. This crank shaft has two crank pins 15 180 apart and disposed between a pair of crank discs which are internally counterweighted. The peripheries of the crank discs constitute the inner races of anti-friction bearings, the outer races of which are secured in the engine crank case in such a manner as to permit expansion and contraction without affecting their'alinenient. Furthermore, the arrangement of one of the bearings is such as to permit slight relative axial movement between its inner and outer faces, to facilitate assembly and to compensate for slight manufacturing variations as well as differences due to expansion and contraction.

The foregoing and other objects, features,

and advantages of the invention will be fully appreciated from the following description in connection with the accompanying drawing, wherein one embodiment is shown by way of illustration, and wherein-- Fig. l'is a longitudinal sectional view through the improved engine;

Fig. 2 is a detail sectional view on a larger scale through the fuel measuring and injection control means, the section being taken in a plane perpendicular to that of Fig. 1; 40

Fig. 3 is a fragmentary detail view of the cylinder and fuel conduit connection; and Fig. 4 is a diagrammatic view of the different cycles of the engine.

This invention was disclosed in my patent application Serial No. 271,725 filed April 21, 1928,v of which the present application is a reflling.

Referring particularly to the drawing, it will be seen that the improvedengine comprises a crank case ill and a pair of opposed cylinders II and I2, the inner ends of which open to the interior of the crank case, while their outer or head ends are curved and fitted with valves as will later be described. The crank case l0 and cylinders H and l2-may be integrally cast as a unit if desired, or they may be separately formed as shown and secured together by bolts or the like, the crank cases being composed of an aluminum alloy or other lightweight metal, and the cylinders being of steel or steel-lined aluminum. Pistons I! of any desired type, are reciprocable in the cylinders II and I2, and are fitted with wrist pins I4 for operative connection of pitmans or connecting rods i5 whose inner ends are connected to crank pins it of a crank shaft which is rotatable in the crank case It. The crank pins ii are shown as being 180 apart, or at opposite sides of the axis of rotation of the crank shaft, and are disposed between two crank discs l1 and I8, which constitute journal portions of the crank shaft. The peripheries of the crank discs are provided with circumferential grooves ii! for the accommodation of steel balls 20, or other rolling anti-friction elements, which are arranged in annular series around the crank discs, and which bear within outer bearing races 2| and 22. The bearing race 2| has a grooved raceway to definitely locate the anti-friction elements 20, while the bearing race 22 has a cylindrical raceway 23 to permit relative axial movement between crank disc l8 and the race 22 whereby to compensate for expansion and contraction of the parts. Said outer races 2| and 22 are further characterized by outwardly extending peripheral flanges 24 and 25, respectively, which are arranged in overlapping relation with annular flanges 26 and 21 in the crank case, and the engaging flanges 24, 26, and 25, 21 are secured together by screws or bolts 28 or other suitable fastening means. With this arrangement the crank case will not be able to expand away from the bearing races in such a manner as to affect their alinement or firm support.

From the foregoing it will be clear that the crank discs constitute bearing races, which, because of their diameters, provide a very substantial support for the crank shaft, and contribute to the desired compactness of the parts. The

crank discs are preferably in the nature of relatively thin-walled shells and are internally counterweighted as indicated at 29 to facilitate smooth running of the engine. The crank pins l5 and inner ends of the connecting rods l5 are also provided with anti-friction bearing members ill, whereby to overcome lubrication difficulties and render the engine more dependable in its opera-- t on. i

When used for aviation purposes, the crank shaft is fitted at one end with a propeller 3| having a stream-line hub and hub cap 32, held in place by'bolts or screws 33. The other or rearward end of the crank shaft has a hub 54 rotating in a fixed sleeve 35, which is provided adjacent the crank disc I8 with a gear 36 meshing-with a planetary gear 31 which is carried by said crank disc. A smaller planetary gear 38 is rotatable with the gear 31 and meshes with a driven gear 39'rotatable on the fixed sleeve 35. The proportions of these gears are such that the gear 35 is driven at half as many revolutions per minute as the crank shaft, and secured to or integral with the gear 39 is a cam 40 which is engaged at op-,

pcsite sides by the inner ends of valve tappets 4|. Rotation of the cam 40 causes the tappets'4l to reciprocate, said tappets extending longitudinally behind the cylinders'll and I2 and being suitably supported by guide members 42 fixed with reference to the cylinders.

The outer end of each valve tappet4l bears against one end of a rocker arm 43 which is pivcylinder and whose other end is intersected by the cylinder axis. Said other end of each rocker arm-45 is provided with a spherical or cylindrical recess 45 on its inner side, for the pivotal connection of one end of a short link 45, the other end of which is similarly connected to the outer end of a stem 41 carried'by a poppet valve 48. This valve 48 controls both admission and exhaust of fluid to and from the cylinder in which it is mounted, and as there is only one such valve for each cylinder it can properly be called a master valve. The valve stems 41 are axially guided for reciprocation in bosses 50 on the cylinder heads, and are normally urged outwardly by compression springs II to hold the valves in closed positions, and the oscillation of the rocker arms 43 by the tappets 4| effect the alternate opening and closing of the valves; Such movementsof the valves are of course synchronized with the movements of the pistons whereby to effect the intake of air, compression, explosion, and exhaust in proper sequence.

It will be observed from Figure 1 that the valves 48 are of relatively large diameter as compared with the bore of the cylinders, thus providing a large valve opening with only a short valve move ment. At suitable predetermined intervals in the cycle, fuel is injected into the cylinders through conduits 52 and 53 from any desired type of injection mechanism 54. The fuel is injected into sion strokes, as desired. In view of the fact that the master valve 45 controls both intake of air and the exhaust of products of combustion, it

will be clear that the valve will be kept reasonably cool, and this is important in that it makes pos sible a higher compression and hence greater power in proportion to cylinder volume. 'In prior art engines using separate intake and exhaust valves, the exhaust valves have become very hot in operation, whereas in the present structure the incoming air during the intake stroke will help cool the valve after each explosion and exhaust.

In the illustrated embodiment of the fuel injecting means, fluid pressure from one cylinder is utflized to force the fuel into another cylinder. To accomplish this a tubular housing I. is mounted upon the outer or rear end of the fixed sleeve 35, and rotatably supports a distributor II which is connected to the engine crank shaft as at O2 to be driven thereby. This distributor 5 I fits snugly in a central bore of the housing I, and is provided with a, recess 63 which is adapted to'periodically effect communication between divergent ports 54 and 55. The conduits 52 and 53 are respectivelyconnected with the ports 54 and 05, and

thearrangement is such that *during the greater part of the cycle, the ports are cut offfrom each other by the periphery of the distributor 5|. At one side, preferably the top, the housing II is provided with aboss which is centrally apertured to intersect the housing bore, and which is connected to a gasoline supply tank from which the fuel is fed by gravity'to the supply port 54.

As the distributor rotates, the recess 88- becomes fllled with the fuel while it supply port 60, and it carries this fuel around to the point where it communicates with the transferpassages or ports 54 and .65.- At thistime, one of the cylinders has a higher pressure than the other, and as a result the fuel in the recess 03 will be blown into the cylinder having the lower internal pressure. In the next revolution the pneumatic draft will flow in the opposite direction, and

' fuel injected during each cycle willalways be of diagrammatically in Fig. 4, and as has been pre-.

other cylinder, with the master valve for air in=-- so the injection of the fuel will' alternate from one cylinder to the other. In the use of light liquid fuels such as gasoline, the fuelwill be vaporized by the heat as it enters the cylinders and so a good mixture is easily produced.

In order to vary the speed of the engine, the cam 40 is tapered, and is longitudinally adjustable by a screw-threaded rod II, which can be manually rotated to shift a finger 1| enz'aains a peripheral groove 12 in the cam. This adjustment varies the stroke of the valve tappets, and thus increases or decreases the valve openings.' The variation in speed of rotation can also be effected by varying the amount of fuel injected, for example, by

the use of needle valves 13 and II mounted in conjunction with the transfer ports 4 and 85, said needle valves being movable by cams I! and 18 which are geared to the control rod 1|. Of course,

other specific adjusting means may be provided as willbeobvlollstothoseskllledinthearhalidthe the cylinders are opposed or in line, or in any other relation. It is to be noted that in practice the transfer ports I and ii are opened simultaneously by the distributor recess '3 as shown in Fig. 2, this structural feature being slightly diflerent in the diagrammatic showing of Fig. 4." Furthermore,

the method and apparatus for transferring the fuel by the pressurein the combustion chamber of one cylinder to the combustion chamber of an- 7 take and exhaust, may be applied to high compression engines if desired.

The improved engine is of extremely simple construction and light weight, and will be strong and durable in service. The invention is suscepcylinder, a fuel d tible of numerous modifications other than those mentioned, and the right is herein reserved to make'such changes as fall within the scope of spirit of the invention.

- the crank shaft, and ineansfor injecting fuel to the cylinders from said measuring device by fluid pressure during their air intake stroke.

2. In an internal combustion engine, a pair of cylinders, a crank shaft, pistons reciprocable in the cylinders and connected to said crank shaft, a single valve in each cylinder for co'ntrollingthe admission of air and the exhaust products of combustion, fuel measuring means associated with the crank shaft, and fuel injecting means utilizing air from the compression stroke of one cylinder to force liquid fuel into the other cylinder dming the air intake stroke thereof.

3. In an internal combustion engine, a plurality of cylinders, pistons operable therein, a crank shaft to which the pistons are connected, fluid conducting means extending from the head end of one cylinder to the head end of another nately to open and to communication the appended claims without departing from the through said fluid conducting means'and to pre-' sent definitely -measured charges of fuel thereto, and means for actuating said fuel measuring device at deflnitepoints in the pistoncycles, and

adjusting means forvarying the flow of fluidthroughsaidfimdeonductingmeanswherebyto control the speed of rotation of the crank shaft.

HUGH ll. 

